This invention relates generally to thermal control coatings, and more particularly to polyaryleneetherketone phosphine oxide compositions incorporating cycloaliphatic units for use as polymeric binders in thermal control coatings and a method of synthesizing such compositions.
Spacecraft such as satellites and deep-space craft are exposed to a wide range of thermal conditions. The high intensity of direct solar radiation can potentially raise temperatures to dangerous levels. Thermal control of spacecraft is therefore important to reduce the absorption of solar radiation as well as dissipate internal heat to proper levels. Temperature control has currently been attained with the use of radiators having thermal control coatings on their surface. Such thermal control coatings typically comprise a potassium silicate binder pigmented with zinc oxide. This white coating exhibits a good initial diffuse reflectance for 380–1000 nm wavelength radiation and a moderate degradation in reflectance upon space environmental exposure. However, potassium silicate is a brittle inorganic glass with very poor flexibility and impact resistance, often showing failures due to film cracking. Another commercially available thermal control coating comprises a methyl silicone binder coating. However, while such a coating has good mechanical properties, it exhibits poor stability in space.
More recently, the use of certain polymers has been proposed for use as coatings in space environments. The use of polymers in thermal control coatings is desirable as they would provide significant weight reduction, good mechanical strength, and exhibit thermal and thermooxidative stability. However, in order to be used as thermal control coatings in space environments, such polymers must also be resistant to degradation by ultraviolet radiation and atomic oxygen.
Accordingly, there is a need in the art for polymers having improved resistance to UV radiation and atomic oxygen degradation which may be used in thermal control coatings.